The BlackGEM Fast Synoptic Survey (BG-FSS)
Optical counterparts to gravitational wave events are expected at depths and time scales that are poorly explored. Other astronomical events may masquerade as possible counterparts. The BlackGEM Fast Synoptic Survey will chart the transient skies on timescales from minutes to days and down to 22nd magnitude. A set of fields will be monitored for two weeks to one month, non-stop, at a cadence of 1-5 minutes, in three filters (u, q and i).